On Tue, Dec 8, 2020 at 2:18 PM Arnd Bergmann arnd@kernel.org wrote:
On Tue, Dec 8, 2020 at 7:21 PM 'Nick Desaulniers' via Clang Built Linux clang-built-linux@googlegroups.com wrote:
On Tue, Dec 8, 2020 at 6:26 AM Arnd Bergmann arnd@kernel.org wrote:
On Mon, Dec 7, 2020 at 11:28 PM 'Nick Desaulniers' via Clang Built Linux clang-built-linux@googlegroups.com wrote:
Hmm...no warnings for me with that config on next-20201208: $ make LLVM=1 -j71 olddefconfig $ make LLVM=1 -j71 ... $ clang --version clang version 12.0.0 (git@github.com:llvm/llvm-project.git 1c98f984105e552daa83ed8e92c61fba0e401410) (ie. near ToT LLVM)
I see CONFIG_KASAN=y in the .config, so that's a recurring theme with clang; excessive stack usage. It does seem a shame to disable a driver for a bunch of archs just due to KASAN stack usage. $ grep KASAN=y 0x9077925C_defconfig CONFIG_HAVE_ARCH_KASAN=y CONFIG_KASAN=y
Is there a different branch of a different tree that I should be testing on instead? Otherwise, can you send the object file?
I was on a slightly older linux-next, and the latest version contains the patch "ubsan: enable for all*config builds" in linux-next, which enables CONFIG_UBSAN_SANITIZE_ALL. It took me an hour to figure out, but after turning that option off, the warning is back.
I'll send you the object for reference in a private mail, it's kind of large.
Got it, thanks.
$ llvm-objdump -Dr --disassemble-symbols=dml30_ModeSupportAndSystemConfigurationFull display_mode_vba_30.o ... 1584f: 48 81 ec a0 08 00 00 subq $2208, %rsp ... $ python3 /android0/frame-larger-than/frame_larger_than.py display_mode_vba_30.o dml30_ModeSupportAndSystemConfigurationFull No dwarf info found in display_mode_vba_30.o $ llvm-readelf -S display_mode_vba_30.o | grep debug_info $ echo $? 1
Can you rebuild+resend with CONFIG_DEBUG_INFO enabled? frame_larger_than.py relies on the DWARF debug info to know what local variables occupy how much stack space.